There are a plurality of ways to evaluate changes or loading conditions of physical components and parts. The evaluation techniques can include both measurement and visual evaluation of the components. For example, physical measurement can be used to evaluate elongation or cracking of components among other device state changes. In addition, visual inspection can be used for the detection of cracks and fractures or other state changes. Furthermore, devices or materials interconnected to a component can be used for the visual detection of changes in the experienced stress or state change of that component or components.
For fasteners or coupled components, physically marking of the fastener or coupled components in the desired orientation can be used to visually identify changes. For example a stripe of paint across a bolt and nut can visually allow one to evaluate if relative movement has occurred. As another example, for a bolt pattern associated with a wheel of a vehicle, non-symmetric markers positioned in a known orientation relative to a nut upon achieving a desired a torque, can also provide a visual indicator of nut movement or bolt elongation.
However, each of these techniques require that one is able to visually inspect the marked location under evaluation, and as such can be a time consuming task when covers or other components impede this visual inspection.
Therefore there is a need for a stress sensitive device that is not subject to one or more limitations of the prior art.
This background information is provided to reveal information believed by the applicant to be of possible relevance to the present invention. No admission is necessarily intended, nor should be construed, that any of the preceding information constitutes prior art against the present invention.